Aspects of the present invention are directed to deadfronted display assemblies and, more particularly, to deadfronted display assemblies having minimized thicknesses.
In space constrained products, the size of a user display area can be limited by spatial requirements. In particular, while the X and Y display dimensions of the display area are important in the user visible interface but may not be limited in terms of their size, the Z dimension can be critical in the overall manufacture of the display assembly and may have stringent size limitations.
Typically, product displays use light emitting diode (LED) indicators for status information, such as power on/off conditions, fault conditions and miscellaneous status conditions. Some displays, such as front bezel display assemblies employ LEDs that are actually located on a separated mother board along with lightpipes to direct the visual status information to the display bezel. Other displays use a display bezel that itself incorporates the LED indicators but is separate from the motherboard.
Front bezel displays are usually affixed to sheet-metal assemblies and generally use embedded LEDs without lightpipes. Here, the LEDs may be surface mounted on the top of a display card in, e.g., a deadfronted display, in which an illumination source is located behind an etched display panel. When the illumination source is turned off there is no visual indication of the message, nor can the characters be readily discerned. However, when the illumination source is turned on, the illumination source backlights the display characters and causes them to be visually noticeable.
In order to provide a properly visible display, both lightpipes and deadfronting display techniques may be required to overdrive the brightness of the illumination source (e.g. an LED). This serves to account for losses in the light path. Overdriving LEDs, however, can reduce their reliability and lifetimes.
In addition, it has been seen that display assemblies may include PCB FR4 material (either rigid or flexible), the deadfront spacer material and the artwork label which has the embedded icons (or characters of choice). Such display assemblies are generally affixed to the visual side of the product. In these cases, the overall thicknesses of the display assemblies are difficult to minimize and lead to sheet-metal deformation.